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New Member

Sorry for the long first post.

I am currently building "The Central Midland" HO-29 layout from the Atlas "Seven Step-By-Step HO Railroads" book. This is the first layout I have built in HO. I have done some N scale on Homasote prior to this.

I am having a problem in a couple of places on the layout. I'm not sure if this is common or due to the fact that I have modified the layout.

The modifications I have made include:

Changing the left side 18" radius curves to 22"
Changing the left side 22" radius curves to 24"
Changing the right side, including the bridges to be double main lines
Removed a couple of recommended spurs

I'm sure this isn't affecting my layout for the problems I am having, but for completeness, I am also making the following changes:

I am wiring this for DCC operation.
I am wiring this completely different than suggested in the text of the plans.
I have gapped the rails for 4 power districts.
One power district is divided into 3 blocks for a grade crossing detector.

I have built up the entire bench work and the main line section of the layout including the double wye. I have not built up the yard and passenger areas yet. I would like to complete the portion I have already built. I am also modifying the yard area layout. I am not going to build the engine yard area either.

The problem I am having involves three locations where the engine I am using for testing derails. This happens only at certain speeds and not others.

The other problem I have is a couple of locations where I didn't notice while building that there are small gaps in one rail where they join. The gap is not really big, but enough that it bothers me.

My questions are:

What are the usual ways to determine the cause of a derailment?
What sort of things should I be looking for?
Are small gaps (under 1/16") okay?
What is usually done to fill gaps?

Here is an image, for reference, from Atlas for the HO-29 layout.

Here are some pictures of what I have built so far. I hope they help.










I can post more pictures if needed..

Thank you in advance,



Pennsy Tuscan Red Blood
The layout is looking great. I like how you made the mainline double throughout the plan. I always wonder why Atlas made it with that one short section of single main. Are you going to put any more sidings for industries in the plan then provided in the original? It seems like a lot of track for only 1 siding spur and that good size yard.


Pennsy Tuscan Red Blood
To answer the "gap" question...

No gaps are good, especially in N-scale. If there are going to be gaps for insulation, you should put styrene in between to maintain the smooth running rails. If you have gaps, the wheels might catch and derail.:eek: Some people might mention expansion and contraction, and the need for gaps. In my opinion, I don't think they are necessary.

Joe Daddy

C & SF, my obsession
Two years ago, I also built this same railroad by the plan.

Check out my web site and blog at Http:// to see some pictures of my old layout.

My modifications were almost exactly identical to yours!
I abandoned the layout after I worked out the kinks (literally) and discovered that it was the classic bowl of spaghetti design. I had lots of derailments caused by kinks and because I followed the plan and used regular boards instead of plywood as roadbed. Those boards warped like the dickens and were a primary reason why I scrapped it. I also had problems because I had mixed Peco code 83 turnouts with Atlas code 83 flex and sectional track.

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(Changing the left side 18" radius curves to 22"
Changing the left side 22" radius curves to 24" )

Not sure if the pix showing what appears to be joint problems is where you made the changes of radius or if the 22" and 24" are even parallel but the pix does appear to be forcing a small radius track into a larger radius curve. What I caught is you added 4" to one radius and 2" to the other. That change might require a lot of adjustment at one or both ends of the curve.

Good looking bench work and it not even cluttered ;o)

Will you be using below bed switch motors? I started out with snap switches and am now converting to Tortoise. It would have been a lot easier to have planned for the below mounting switches than to try to mount them after. Murphy is having a good time under the layout with braces and ribs!! Seems there is a brace under every turnout.

We're havin' fun now :eek:)


Well-Known Member
Power districts

Ed the bench work looks great but I don’t understand the reason for the four power districts. Do you mean four signal blocks? Four power districts mean four power boosters. That’s a lot of extra cash for no reason that I can think of.



New Member

Thanks for all the kind words! I will respond to all the post so far below.

The wye works fine so far. There are four insulators in the rails to allow for the operation of a PSX-AR for the unbuilt yard area.

I haven't decided about industries yet but plan to add spurs as needed.

The gaps do bother me, but none are causing problems yet. You mentioned "styrene" as a way to fix gaps. Could you post some more information about this.

Joe Daddy...
Thanks for the links to your slide show! I nave no warping yet (fingers crossed).

Jon NFL...
One of the problems I am having is right in the middle of the left side 22" modification. I see no problems with the tracks and don't 'feel' anything out of place, but at some speeds the engine derails. I will do some measurements to verify that I have the correct diameter for the 22" radius tracks.

Regarding the four power districts...
Maybe I am using the wrong term. What I mean is I have four areas that are fed from the same booster through four circuit breakers (PSX-4). I did this for protection and signaling.

I did figure out one of the derailments I was having, although I feel sort of like an idiot for this one.

Upon further inspection of the area with the problem, I noticed a small bump in the road bed. I investigated further and found a single track nail under the road bed. I removed the nail by sliding a small putty knife under the road bed removing the nail , the problem disappeared.

Thanks for the ideas and comments.



Fleeing from Al
I was going to suggest the you already own the two best tools for finding track problems - your eyeballs and your fingers. :) You've already found one problem that could easily have been found by just running your finger down the roadbed. Get right down on the rail and eyeball each track, especially the curves. Kinks and radical changes in curvature will be unmistakable and will have to be fixed. Run you fingernail along the top surface of each rail, including the switches. If your fingernail catches on something, there a good change your rolling stock will as well. Have a small flat file with you to to take care of those problems as you find them. Lastly, use you finger to run down the center of the grade between the two rails and feel for bumps or things that aren't level. Get those taken care of too. When I do this, I find 90% of my problems are solved. A small gap in the rail joint, especially on straight track, should be no problem. I have one side track which, due to...ahem... a small builder's error, has a gap which is nearly 1/2". I coudn't fix it without tearing up abut 50 feet of track so I decided to just run the trains over it and see what happens. It's probably the one place on the layout I've never had a problem. :) A 1/2" gap is pushing it but it shows that most wheels are pretty tolerant of gaps and gaps are rarely the cause of derailments, at least on straight tracks.


Chief Test Pilot
I noticed in the pics that you're using pine boards as the sub-roadbed. I would be very cautious since these will warp (they have a tendency to "cup"). If you have to use them make sure they are screwed down securely every foot or less.

One other comment, and this is just my opinion so take it for what it's worth; you have a huge "bowl of spaghetti" going on there. I'm assuming the main yard on the lower left of the track plan is on a second level below the main line? Also, that "double track, double wye" you have going on on the right side (that ties the two loops together) looks like a wiring and operating nightmare.



I am currently building "The Central Midland" HO-29 layout from the Atlas "Seven Step-By-Step HO Railroads" book. This is the first layout I have built in HO. I have done some N scale on Homasote prior to this.

I am having a problem in a couple of places on the layout. I'm not sure if this is common or due to the fact that I have modified the layout.
I would strongly suggest that you utilize 3 foot sections of flex track rather than the shorter segments of fixed radius track. It is much easier to get a smooth curve than the many 'minor kinks' I see in your track. These kinks will manifest themselves in many derailments both in curvature and elevation discrepencies.

From what I see you will FOREVER have problems with derailments. Take a good 'wood paint sturr stick' and lay it on edge across the tops of your rails to see the height variations. For really finding subtle derailment spots run a 6-axle diesel engine with very small flange wheels across suppect portions of rail (like an Spectrum), and 3-axle truck will tend to rest on just two of the axles allowing the 3rd overhanging one to derail with the small flanges not preventing it. If you can run this engine around the layout without derailments then you have some pretty good track work.
WARNING: You may have to do a lot of 'shiming' with thin plastic scrapes to get everything working properly.

Here are some pics of my modified Central Midland layout (HO), that I may have to sell soon as I may move out of the country.
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...a few more. (Gosh I wish had more time to work on this layout... the Theme was working out good)



HO Scale Train Layout, Central Midland (modified)

This trackplan is largely based on John Armstrong’s design, commissioned for Atlas Model RR, “The Central Midland”, plan #HO-29. But mine is in the ‘reverse image’ of the original, and modified in a couple of significant manners. Basically 10’x12’, plus.

Many model RRs are condensed versions of actual prototype RRs. This RR is not one of those. Rather it is a very condensed version of as-large-a-number of different scenes as one might find on a wide variety of model RRs. Per some of the ‘backdrop signs ’posted in the photos, it was intended that the trains would travel through a mountainous scene, thru the rolling foothills of farmland, and thru a big cityscape.

That’s a pretty tall order for such a small model RR. Some might say too much, but I believe once it is all finished and scenery added with trees, rocks, painted backdrops, etc, it can pull it off.

This RR is for someone who likes to run trains, as well as do some intricate switching work. You can put the twin mainlines into continuous running mode, while you deal with the intricate movements of steam engines in the roundtable/roundhouse area, supplying the coaling tower, diesel & freight yard train shuffling, container loading, quarry & warehouse sidings, and the make-up of trains in the staging area. You can also manage to turn some very long trains around to run the layout in the reverse direction via the double wye’s, and the extended tracks of the additional staging area.

There are basically 4 scenic zones. Three are enclosed by 3 big loops of the mainlines; 1) a mountainous scene, 2) a combination of farm house/pasture land and rock quarry, and 3) a roundtable scene. 4) The fourth zone would be that of the freight yard and container facility.

Roundtable Zone
I’ve always favored steam engines for their intricate nature and great variety of forms. So naturally there is a steam engine turntable and repair facility. And why not put this right up front where one’s collection of steam engines can be on display. This steam display replaces the diesel facility of the original Atlas plan. It features:

a) A fully operating turntable capable of handling a BigBoy or Allegheny.
b) A roundhouse, and several different repair shops
c) Outdoor track stowage (nice display of steam roaster)
d) A water tower and diesel fuel tank
e) A twin track coaling tower
f) A twin track bridge crossing to this steam facility from the freight yard.

Sub-Roundtable Loop
Below the roundtable scene I’ve added a full circular ‘subterranean track loop’ with several spurs branching off to 1) a fuel oil depot, 2) a production factory/warehouse, and 3) and a stone quarry/loader situated over in the adjacent mainline loop. The stone quarry will feature its own particular rock style wall at the inner perimeter of the surrounding track. There is provision (another turnout) for another spur line that would go out into an industrial park scene (or whatever), yet to be built off to the left of this subterranean loop. Switchers (both steam & diesel) can do continuous running on this subterranean loop

Freight Yard Zone
The original freight yard now has 8 tracks rather than 6, and significantly more services:
a) A planned duel track diesel engine house where the photos now show the cluster of diesel engines.
b) Possibly install a small Walthers diesel locomotive transfer table
c) A diesel engine fueling & sanding facility to be located between the tracks coming into the yard from the big ‘wye’ and those tracks going over the bridge to the steam area.
d) A primary water tank along with a water loading bridge to service all locos leaving the railyard and steam service areas.
e) Several control towers, including a primary one at the double wye, a primary one at the yard entrance, and several smaller elevated ones inside the yard. There are also floodlight towers thru-out the yard, and one or two in the steam service area.
f) There is a propane tank stowage facility off to the side of the yard, with several siding-tracks to ‘display’ a variety of tank cars. There is also a butane tank and loading fixture as well. The propane area shares a ‘parking lot’ with a farm/fertilizer building.
g) At the far end of the yard there is a container loading/stacking facility with cranes and multiple stacks of containers. There are corner mirrors standing at the edges of this scene that act to reflectively ‘double the size’ of this container yard, and also make the freight yard appear twice as long as it is.
h) The yard tracks turn 90 degrees at this container facility and enters a 6 track wide staging area. If a one or two of these staging tracks are left empty, then very long trains can be backed in from the mainlines and turned to run in the opposite direction via the ‘double-track wye’ formed at the entrance to the freight yard.

Long Trains
Very Long Trains Can Be Run on This Relatively Small Layout….25-27 cars. (With all of the multiple scenics in place, these very long trains won’t appear to be ‘chasing their tails’)

Mainline Track
There is a mainline of over one-and-a-third scale miles in length, which is mostly double track. The dbl tracks neck down to a single track across a scratch built truss bridge.

Doubletrack Mainlines
I made another significant modification to the trackplan that would allow for continuous double train operation without regards for the original single-track bridge restriction. This consists of a curved ramp that shortcut-links the upper inner mainline with the lower inner mainline in the ‘access hole’ area destined to be hidden by a removable foam mountain structure. This link rail is a steep grade, but I have been able to run long trains both up and down the grade without derailing. I also included protective barriers on the sides of the ramp to contain any derailments. Two long trains running in the same direction get out of phase due to the difference in the length of the two loops. Two trains in opposite directions is quite photogenic as well.

There’s a River Running Through It
That prominent single-span truss bridge at the center of the layout is intended to span both a lower track and a river/creek that originates with a cascading waterfall located in the ‘mountain loop zone’. This creek then flows right to left bounded between the edge of a farm pasture land that hides the sub-lower tracks in front of the farm supply building, and a rock cliff face on which the upper rail line runs between its two single-span bridges. It then exits out under the single & double span bridges at the rear of the layout, and into the painted backdrop scene labeled “rolling farmland”.

Rolling Farm Backdrop
I’m sure you’ve seen the smooth rolling ridges that mark the transition at the base of mountains to the flatter lands. Then imagine a series of rolling ridgelines stretched horizontally across this backdrop to transition from the mountain scene on the right, to the outskirts of the city scene on the perpendicular backdrop at the left. Our stream/river will meander out thru the shallower portions of these ridges, and there will be cattle grazing on these grasslands. A very distinctive cattle billboard sign will announce to the train passengers that this is a major ranch (I have a great photo already). Maybe a rural hwy as well, and another farm with silos in the distance….all painted-on of course.

The symbolism here is the trek from the east coast city of Baltimore to the western mountains, either the Appalachians or Sierras. This model-rr can run many different RR marques, from the east coast to the west coast.

City Scene Backdrop
This could be the most exciting scene of all. My plan was to make this a city scene of Baltimore, an industrial city, home of the nations first railroad, and home of the famous B&O. There would be two distinctive images I thought I would include; 1) the infamous ‘Bromo Selzer’ tower*, and 2) the Mt Royal train station**. The train station in particular, as I had no room on the layout for a model station. I imagine it could be painted onto the backdrop, and include a dbl track portion that would appear to join the actual mainlines over in the back corner of the layout.

There are lighting techniques, layering techniques with poster board materials, and thin single-sided plastic structures that could make this city scene come alive, even in its very ‘flat presentation’. I have some sample illustrations.

Coal was, and is very much a part of Baltimore’s history along with steel and railroads. I had thought it could be possible to paint a coal fired power plant or steel mill onto a portion of this city scene down on the lower left hand side near the roundhouse area. Maybe add a large pile of coal alone with a string of coal cars waiting to be unloaded. If the layout were spaced out a bit from this wall/backdrop, it might be possible to insert one or two ‘fake’ sidings with coal cars and/or B&O passenger cars in waiting.



Description (continued)

Mountain Zone
This scene holds a lot of promise as well, depending upon the extent to which one wishes to fulfill it. First off, forget the mountain posters shown in the photos. They are incorrect mountains…I am not suggesting the ‘alps’ here, but rather ‘logging’ type mountains you see in the foreground of these posters. In its simpler form, the two 90 degree backdrop walls could both be posters of mountains, and the loop of tracks would be covered with a large foam mountain scene that would lift out for access to the trains. This foam mountain could be hollow inside to allow for access to the tracks from underneath without having to lift it out of place. Quite a variety of track entrance/exit portals could be experimented with while various portions of trackage is exposed, or covered, with the trains running under, or beside, a cliff in the mountain. There might even be several ‘interchangeable’ mountain dioramas; 1) Appalachian, 2) old time Western scene, 3) logging scene, 4) your imagination.

In my imagination I would try to create a continuous–loop track for short logging trains that would meander through and around this foam mountain diorama. The ‘centerpiece’ would be the track crossing a steep wood trestle structure bridging over a waterfall (vertical falling stream) sculptered into the front face of this mountain. (I just had to get one more bridge on the layout, and it needed to be a mountaineers trestle type). This waterfall would feed my river/creek that runs through the layout.

The track is all code#100 nickel-silver that has been painted a rust color to hide its extra rail height (except incomplete in the railyard). The plastic ties have all been stained also, and with the addition of ballast, it should look quite scale like. A whole lot of effort has been spent to make the rail connections, elevations, transitions, etc as smooth as possible to avoid derailments. Trouble-free operation has been a constant goal, and even to include the backing down of long trains. This ‘no-derailments’ operation was sought out to be excellent prior to any ballasting.

DCC was to be added later when things got all sorted out, both with DCC itself, and with this layout itself. In the meantime there is a very complete block system installed, and different from the original Atlas plan in the expanded freight yard, and the newly designed zones such as the steam area, the new loops under the turntable, and the added staging area.

The isolation blocks and the reversing sections are all controlled by traditional Atlas brand switches built for these purposes. Even after DCC is added, these numerous blocks will allow for seeking out and isolating a particular problem area.

The original 3 power packs have been replaced with 4, and these are not cheap small units, but rather the MDC 6200, “Sound & Power” units. One power pack each for the two main lines, and two more throttles for the freight yard area, the steam area, and the loop industrial area. Two power packs can be linked to the yard areas and turntable areas each, so multi-train operation is possible. There is a master throw switch which allows the engr to utilize all of this new functionality, or to revert back to the original Atlas wiring plan. The addition of DCC would eliminate some of this complication of using multiple power packs and blocks to control many trains in the freight yard and the roundhouse areas. There is a spare 6200 power pack that temporarily powers the turntable. Its ‘sound’ function can also be utilized to supplement sounds in the steam or diesel mode without the turntable also operating.

There is also another hi-tech sound & power system from an earlier era. Complimenting this FYFFE unit is a brand new decoder for this unit. Maybe experiment with another sound system.

The entire electrical wiring system is quite elaborate, but very well organized and bundled up nicely. There are split-connectors pre-wired in to allow the layout to be broken down into three sections for relocation purposes.

The traditional Atlas turnout controls are NO longer utilized. Several capacitor-discharge units now power the turnouts when a zone button is pushed. There are toggle switches placed at each turnout location on the track plan diagrams, and their ‘handles’ are oriented so as to indicate the direction in which the track turnout is thrown. So choose the train’s route, throw all the applicable toggles to the desired direction, and then press the ‘zone button’ to activate the turnout operation.


Joe Daddy

C & SF, my obsession
Thanks for posting the photos of your layout. I always like looking at how things are turning out. I've not really thought much about my first layout for a long while, but your pictures and comments churned up the cinders in my old noggin.

My second layout wound up with too much track in too little space, (Bowl of Spagetti) and it had less track in a larger space than the Midland Central. I'm glad that I have the space for a more spread out railroad.

Good luck with your Midland Central.

Joe Daddy


Click on the picture to see a slide show of the layout.
Looks like yours was a 'reverse image' as is mine.

Agreed it was a bit 'busy' in this size, but I got a lot of different scenes into a relatively small layout.

I also managed to divide it into three sections so it could be removed from the house without cutting it up.

grande man

Bonafied Grande Nut
railandsail, I think you can pull it off too. A creative use of scenery viewblocks will work wonders. Don't let the spaghetti bowl comments turn you off. This is an old school layout. For some reason I find that appealing. I can't wait to see it finished!

BTW, the flextrack suggestions are good info.
Don't let the spaghetti bowl comments turn you off. This is an old school layout. For some reason I find that appealing. I can't wait to see it finished!

Ditto. Although I'm building a once-through-each-scene narrow-shelf-around-the-walls layout right now, it's only because I have the space for it. If my space was more constricted, I'd use the spaghetti-bowl approach because for me running trains is what model railroading is mostly about.

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